Most vehicles have rigid roof structures that permanently extend over and cover the passenger compartment. Manufacturers also provide a variety of designs that offer the vehicle operator the opportunity to partially or completely uncover the passenger compartment. Sunroofs and moonroofs are some of the simplest designs, and offer the opportunity to open a portion of the vehicle roof for increased airflow. More complicated designs allow the entire roof structure to be retracted and stored behind the passenger compartment.
Retractable roof systems generally fall into two categories. The most common type of retractable roof design is a convertible soft top or roof. These designs include an articulating structural framework with a flexible cloth or plastic outer skin. In an extended position, the front end of the articulating framework connects to a header above the vehicle windshield and the outer skin extends over the passenger compartment. When retracted, the articulating mechanism, along with the outer skin, fold into a compact shape. While convertible soft tops offer the choice between a covered or uncovered passenger compartment, they also suffer from several disadvantages in comparison to traditional rigid roof structures. Vehicles with soft tops are typically less well sealed against the elements and are somewhat noisy. They are also less resistant to break-in attempts and have a less finished interior appearance.
The other retractable roof design is a retractable or folding hardtop roof system. Retractable hardtops consist of one or more rigid roof elements that are mechanically articulated such that they can be repositioned into a storage area behind the passenger compartment. Because the retractable hardtop consists of rigid sections, the system can provide a much closer approximation of a traditional rigid roof structure. In the extended position, a retractable hardtop securely covers and seals the passenger compartment, giving the appearance of a permanent roof. A retractable hardtop does a significantly better job of sealing the passenger compartment, reducing noise, and preventing break-ins. However, the retraction and storage of the hardtop presents significant mechanical challenges. Typically, when the retractable hardtop is in the retracted position, it resides in the portion of the vehicle traditionally provided for storage, such as the vehicle's trunk. While the storage space may be completely usable when the hardtop is in the extended position, most consumers prefer not to sacrifice the use of the storage position when the roof is retracted. There is generally a tradeoff between storage efficiency and mechanical complexity.
Most modern retractable hardtop designs consist of two or more articulated sections that are automatically folded or stacked in the storage area. In one design, referred to as a “clamshell” design, the roof structure is divided into a front section and a rear section. The front and rear sections are pivotally interconnected and the rear section is pivotally connected to a support structure behind the passenger compartment. Examples of clamshell type retractable hardtop designs are shown in U.S. Pat. No. 6,217,104 to Neubrand, and U.S. Pat. No. 5,785,375 to Alexander et al.
In a clamshell design, the front and rear sections may both be said to have an inner and an outer surface, with the outer surfaces cooperating to form the outer surface of the roof structure when in the extended position. When retracted, the front section folds so as to bring the inner surface of the front section towards the inner surface of the rear section, and both sections are together positioned into the storage area. Often, the deck lid of the vehicle articulates into an out-of-the-way position to allow the hardtop sections to move into a position in the trunk. The deck lid is then repositioned to cover the pair of roof sections. In most designs, the front and rear sections both have generally convex outer surfaces and concave inner surfaces. Therefore, when the inner surfaces are folded towards one another, the concave shapes cause there to be a significant distance between the mid-portions of the folded front and rear sections. Consequently, clamshell designs do not store as compactly as some other designs. Their advantage is that they are significantly less complex than most other designs. Reduced complexity not only reduces manufacturing costs, but also improves reliability of the system. Clamshell designs also have better structural integrity than some other designs.
An alternative design, which provides improved storage efficiency, may be referred to as a “stacking” design. Again, the roof is divided into two or more sections. However, when the hardtop is retracted, the roof sections are stacked such that the inner surface of one section is adjacent to the outer surface of another section. Because each section typically has a concave inner surface and a convex outer surface, placing the inner surface of one section next to the outer surface of another often results in more efficient space utilization. Examples of stacking retractable hardtop designs are shown in U.S. Pat. No. 6,336,673 to Rothe et al., U.S. Pat. No. 6,318,793 to Rapin et al., U.S. Pat. No. 6,053,560 to Rothe, and U.S. Pat. No. 5,979,970 to Rothe et al. As will be clear to those of skill in the art, stacking designs require significantly more complex articulation mechanisms than clamshell designs. This increased complexity leads to increased costs, reduced reliability, and reduced structural integrity.
There have been several attempts to provide clamshell designs with improved packaging. In one approach, the rear window or backlight is articulated in some manner to increase the space between the outer surface of the backlight and the bottom of the trunk. In a typical clamshell design, after the front and rear sections are folded into the trunk, the rear section, including the backlight, is positioned under the front section, and the outer surface of the rear section and backlight face the bottom of the trunk. Typically, the rear section has an outer surface that is convex, and therefore curves toward the floor of the trunk. The backlight, especially where the backlight forms a substantial portion of the rear section, is the component positioned nearest to the bottom of the trunk. Also, there is typically a significant gap between the inside surface of the rear section and the inside surface of the front section when they are clam-shelled together into the trunk. Articulating backlight designs move the backlight upwardly into the space, so as to reduce the amount of wasted volume.
PCT Publication No. WO 01/62533 A1 to Queveau discloses a clamshell style folding hardtop with an articulating rear window that is pivotally connected to the front roof section near the front edge of the rear window. The window is hinged to the side sections or C-pillars of the rear roof section close to the rear of the window. This design allows the rear window to remain closer to the front roof section when the hardtop is stowed.
U.S. Pat. No. 6,086,136 to Jambor et al. discloses a clamshell style roof with an articulating rear window having its rear end pivotally interconnected with the remainder of the rear roof section. A drag lever has one end connected to the rear window, forward of the pivot, and the other end connected with the vehicle body. As the hardtop moves to its stowed position, the drag link causes the window to rotate about the pivot such that the end of the window nearest the front roof section moves upwardly.
U.S. Pat. No. 6,131,988 to Queveau et al. discloses a clamshell style articulating hardtop wherein the rear window is supported by the C-pillars using a rotational connection, which allows the rear window to flip over with respect to the remainder of the rear section during retraction of the hardtop. This positions the rear window at a distance above the remainder of the rear section and positions it close to the underside of the front roof section.
U.S. Pat. No. 6,425,620 to Schutt et al. discloses a clamshell style retracting hardtop with a rear window that is pivotally attached at its rear end to a cross member that forms part of the rear roof section. An articulating mechanism interconnects an intermediate portion of the rear window with the C-pillars and moves the window upwardly towards the front roof section during retraction.
U.S. Pat. No. 6,390,532 to Mac Farland discloses a stacking retractable hardtop design wherein the rear window articulates upwardly with respect to the remainder of the hardtop during retraction. The upper end of the rear window is pivoted to the remainder of the rear section, with the rear portion of the window being linked to both the body and the C-pillar.
While each of the above designs offers some benefits in terms of space efficiency, they each have certain limitations that limit their use. Consequently, there remains a need for retractable hardtop designs that offer an improved compromise between space, efficiency and mechanical complexity.